Rotor assembly



, Nov. 2, 1.943 H, ROE 2,333,200

} ROTOR ASSEMBLIES Filed Nov. 8, 1941 IN VENTOR.

W A- IQ", MM

Patented Nov. 2, 1943 ROTOR ASSEMBLY Howard A. Roe, Elyria, Ohio,assignor to The General Industries Company, Elyria, Ohio, a

corporation of Ohio Application November 8, 1941, Serial No. 418,378

4 Claims.

My invention relates to rotor assemblies for induction motors andrelates more particularly for such rotor assemblies as are utilized inconnection with small induction motors.

In certain prior assemblies with which I am familiar straight conductorbars of copper are inserted in the rotor core and copper end plates areprovided on either side of a plurality of laminae making up the rotorcore, the ends of the rotor bars being bent over, thus anchoring theconductor ends of such copper rods together and also binding the corelaminae together.

It is an object of the present invention to so construct the rotorassembly of my invention as to eliminate the use of copper end plates.

Another object of my invention is to so construct the improved rotorassembly of my invention as to enable the same to be conveniently andquickly assembled, a minimum of parts being utilized therein, suchassembly being inexpensive to manufacture and highly efficient in use.

A further object of my invention is to provide an improved rotorassembly wherein the contactlng end portions form a solid ring ofcontacting material.

Other objects of my invention and the invention itself will becomeapparent from the following description, reference being had to theaccompanying drawing wherein a preferred embodiment of my invention isillustrated, wherein:

Fig. 1 is a top plan view of the rotor assembly of my invention;

Fig. 2 is a side elevational view of the rotor of my invention;

I Fig. 3 is a sectional view of the rotor assembly of Fig. 2;

Fig. 4 is a sectional view taken on the line AA of Fig, 1, the rotorshaft of Fig. 1 being omitted from this figure;

Fig. 5 is a fragmentary plan view of the conductor bars of Figs. 1 to 4inclusive showing the.

same after an intermediate crimping operation; Fig. 6 is a top plan viewof the conductor bars of Fig. 5 showing the same in their finalposition, as more completely illustrated in Fig. i and Fig. 7 is asectional view of the rotor assembl similar to Fig. 4.

Referring to the figures of drawing, l0 represents a rotor shaft uponwhich is mounted a core II which is preferably composed of a pluralityof laminations l2 superimposed upon each other, preferably formed ofiron or alloy steel discs, the said discs being disposed in a pile, asstated, superposed one upon the other.

A plurality of equidistant perforations l3 adjacent the outer peripheryof each of said discs II are suitably aligned whereby rotor conductorsll preferably constructed of copper or equally good conductive materialmay be projected therethrough. Saidconductor bars I! are straightthroughout the greater part of their length and have tapered endportions I5 and i6 and said.

bars, after being-projected through the stack of core laminations sothat equal lengths thereof project from both core ends, are then bent orcrimped, as shown in Fig. 5, thus compressing the core laminationstightly together and then the tapered ends l5 and iii of said bars arebent simultaneously to high pressure in order to securely bind the sametogether whereby an emcient conducting ring is formed.

1 am aware that numerous and extensive departures may be made from theembodiment herein illustrated and described without however departingfrom the spirit of my invention and the scope of the appended claims.

I claim:

1. A squirrel-cage type rotor for a dynamoelectric machine comprising astack of magnetizable discs, relatively spaced bars threaded intraperipherally through the discs and having 'outwardly projecting ends,said ends abruptly bent toward the stack axis and swedged against thestack end surface whereby said bar ends are flattened and broadened toeifect lateral pressure engagement between the adjacent side surfaces ofadjacent bar ends and to firmly hold said discs in operative stackedrelationship.

2. A squirrel-cage type motor rotor comprising a co-axial stack ofmagnetizable discs, a plurality of substantially parallel conductor barsthreaded intraperipherally therethrough, and having end tips projectingbeyond the flat end surfaces of the stack, said tips at each end of thestack, abruptly bent axially inwardly of the stack in relativelyconverging directions, and deformed by flattening pressure against saidstack end surfaces to so increase the width of the converged tips,whereby the laterally expanded tips each exert such lateral pressureagainst adjacent tips as to effect a low resistance to electricalcurrents traversing the annular circuit of said contacting tips.

8. A squirrel-cage rotor for a dynamoelectric machine comprising a stackof magnetizable discs, and a plurality of substantially parallelelectrical conductor bars threaded through said discs and having endportions projecting beyond the stack at both ends thereof, the portionsof said bars located in the region of emergence from the stack being inrelatively substantially spaced circular arrangement concentric with thestack axis, each projecting bar portion being abruptly bent in saidregion to deflect its tip laterally inwardly towards and against aportion of the end surface of the stack which is disposed between thestack axis, and the aggregated widths of said tips being slightlygreater than the circular dimensions of the annular space into whichsaid tip is moved by said bending as to effect wedging compressivestresses to be exerted by each tip against contiguous engaged sides ofthe adjacent tips, whereby good electrical conducting contacts areeffected between the ring of engaged tips.

4. A squirrel-cage type rotor for a dynamoelectric machine comprising astack of axially aligned magnetizable discs, all provided with a seriesof spaced intraperipheral openings, and a plurality of electricalconducting bars each threaded through corresponding openings of all saiddiscs, each of said bars being generally of U-form, the yoke of each barenclosed with the stack and the end arms being abruptly turned from saidyoke inwardly along the adjacent end surface of the stack in the generaldirection of the stack axis, and the lateral confronting surfaces ofcorresponding arms of adjacent bars, progressively converging proceedingtoward said stack axis, whereby said confronting surfaces, in theregions of the arm tips, are caused to contact, the radially inwardlydisposed tip portions of all of said arms being additionally flattenedagainst the adjacent stack end, to increase the contact pressure exertedlaterally between said adjacent contacting arm tip surfaces to providean annular electrical conducting circuit comprising the interengaged armtips.

HOWARD A. ROE.

